Hello. My device is USB composite (1.1), and the interface I am working on
is for ASIO (audio) streaming.
I have two questions for USB pipe flags:
a) What do USBD_PF_ENABLE_RT_THREAD_ACCESS and USBD_PF_MAP_ADD_TRANSFERS
actually do? The DDK says that the former is enables optimization for
streaming transfers while the latter enables “fast isochronous mode”. Can
anyone shed light on what these actually do?
b) Since I have a composite device, I use URB_FUNCTION_SELECT_INTERFACE
instead of URB_FUNCTION_SELECT_CONFIGURATION to allocate bandwidth and
receive my pipes. However, the DDK implies that the aforementioned flags
(see above) work for URB_FUNCTION_SELECT_CONFIGURATION. Does this mean that
they are inaccessible to me, as I am forced to use these flags in my
URB_FUNCTION_SELECT_INTERFACE request?
thanks,
Philip Lukidis